We know that vertically opposite angles are equal.
So, e = 41° [Vertically opposite angles]
We know that linear pair of angles are supplementary (180°).
So, f + 41° = 180° [Linear pair of angles]
=> f = 180° - 41°
=> f = 139°
and d + 90° = 180° [Linear pair of angles]
=> d = 180° - 90°
=> d = 90°
